Enhancing data envelopment analysis: a comprehensive calibration with random forests

Table 7 Descriptive statistics for the estimated efficiency levels grouped by environmental variables

Models	Mean	Std. Dev.	Min	Q1	Median	Q3	Max
DEA
All	0.6424	0.1932	0.0407	0.5301	0.6394	0.7610	1.0000
OECD	0.7012	0.1424	0.3948	0.6002	0.6947	0.7741	1.0000
Non-OECD	0.5930	0.2156	0.0407	0.4486	0.5741	0.7429	1.0000
1990	0.6747	0.1886	0.2326	0.5520	0.6317	0.7817	1.0000
2000	0.6294	0.2272	0.1305	0.4633	0.6674	0.8125	1.0000
2010	0.6270	0.1702	0.1855	0.5203	0.6355	0.7285	1.0000
2019	0.6386	0.1820	0.0407	0.5524	0.6385	0.7653	1.0000
RF-DEA
All	0.7344	0.1491	0.2019	0.6435	0.7380	0.8301	1.0000
OECD	0.7779	0.1112	0.5375	0.6956	0.7619	0.8447	1.0000
Non-OECD	0.6979	0.1664	0.2019	0.5751	0.6905	0.8185	1.0000
1990	0.7709	0.1337	0.5168	0.6781	0.7392	0.8314	1.0000
2000	0.7271	0.1716	0.3532	0.6096	0.7234	0.8581	1.0000
2010	0.7153	0.1337	0.3557	0.6287	0.7375	0.8095	1.0000
2019	0.7245	0.1505	0.2019	0.6436	0.7367	0.8251	1.0000